1. Field of the Invention
The present invention relates to a controlling device and, more particularly, to a controlling device for a coil spring bending tool and to a controlling method thereof.
2. Description of Related Art
A device for controlling an outer diameter of a coil spring in a conventional coil spring forming machine has shortcomings of being produced for a high cost and of difficulty for operation. For example, most advanced countries like US or Europe normally use multi-axis numerical control motors to control an automatic machine. Japan uses two numerical control motors to control each coil spring bending tool of the conventional coil spring forming machine. Since at least four numerical control motors were used, an absolute coordinate is therefore adopted to the conventional coil spring forming machine.
The absolute coordinate is engaged of obtaining locations of each coil spring bending tool by calculating trigonometric functions from an absolute origin point. The complex calculation requires a high-end computer to complete and to further accomplish by various gearing devices. Especially for producing a coil spring with multiple diameters like hourglass-shaped, olive-shaped or cone-shaped, the numerical control motor sometimes needs to wait for the high-end computer to complete the complex calculation which leads to a cost increase and which prevents automation of a small size coil spring forming machine.
To overcome the shortcomings, the present invention provides a controlling device for a coil spring bending tool to mitigate or obviate the aforementioned problems.